Treatment of a Munitions-Manufacturing Waste by
the Fixed Activated Sludge Process
RICHARD C. ALBERT, Pollution Control Engineer
Planning and Grants Division
Virginia State Water Control Board
ROBERT C. HOEHN, Assistant Professor
Virginia Polytechnic Institute and State University
CLIFFORD W. RANDALL, Associate Professor
Virginia Polytechnic Institute and State University
INTRODUCTION
The objectives of the research project described in this paper were to determine
whether a munitions-manufacturing waste could be treated successfully by a process known
as the "fixed activated sludge process" and, if such treatment were effective, to accumulate
the data necessary for describing the kinetics of the system. The mode of treatment differed
from conventional activated sludge processes in that attached, filamentous
microorganisms, rather than suspended, flocculent biomasses, were the active biota. The
waste was one of several originating from the manufacture of explosives and related
products for the military.
Several of the wastes from this industrial complex are discharged to a small creek that
flows into one of the. largest rivers in Southwestern Virginia, and downstream of the
outfalls, prolific growths of filamentous microorganisms can be observed during most times
of the year. These "sewage fungus" beds are evident not only in the creek but in the river as
well below its confluence with, the creek. It was because these wastes apparently are
stimulatory to filamentous microflora that treatment of the waste by the fixed activated
sludge process was investigated.
The Waste
The particular waste selected for treatment during this research program originated
from the manufacture of a propellant used in 105 millimeter artillery shells. The
manufacturing process consists of the following operations:
1. Nitrocellulose is mixed with alcohol to form a colloidal mass of "dough"
that is subsequently shaped into blocks.
2. The blocked dough then is blended thoroughly with ether, dinitrotoluene (DNT),
and other ingredients, depending upon the exact formulation desired.
3. The dough is blocked once again and then extruded through dies, resulting in
strands having a fixed number of perforations. The strands subsequently are
cut to a specified length and transferred to a solvent recovery area.
4. In the solvent recovery area, the cut powder is washed with water previously
heated to 60 C. This step removes some of the residual solvents and DNT from
the perforations within the pellets. After the wash with water is completed, the
pellets are purged with methane gas to remove the final traces of the solvents.
The solvents actually are recovered only from the methane.
The water used in the washing operation, referred to as "water-dry waste," contains,
principally, ethyl alcohol, diethyl ether, and DNT. During normal operations, no effort is
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